Recuperative soaking pit furnace



Aug. 15, 1939. w. A. MORTON ET AL RECUPERATIVE SOAKING PIT FURNACE Original Filed July 5, 1934 Patented Aug. 15, 1939 UNITED STATES PATENT OFFICE RECUPERATIVE SOAKING PIT FURNACE William A. Morton, Mount Lebanon, and Howard F. Spencer, Pittsburgh, Pa., assignors to Amco. Incorporated, Pittsburgh. Pa... a corporation of Pennsylvania 4 Claims.

This 'invention relates to new and useful improvements in furnace door operating mechanism and the present application is a division of an application serially numbered 32,534 filed July 5 22, 1935, which is a division of an application serially numbered 733,812 filed July 5, 1934.

The invention is especially adapted for fuel fired furnaces such as soaking pit furnaces or the like from which the charge is periodically removed and new charges entered without materially interrupting the normal operation of the furnace. Obviously, such intermittent exposures of the heating chamber result n a great loss of heat, and it is, therefore, among the objects of 15 the invention to not only provide for a cover constructed to efficiently seal the heating chamber when in closed position, but to reduce the heat loss to a minimum during the opening and closing movements thereof. To this end, provision is made to seal the cover with the furnace roof or wall when in the closed position and to maintain a partial seal thereof during the opening and closing movements.

The invention will become more apparent in connection with a description of the accompanying drawing constituting a part hereof in which like reference characters designate like parts and in which:

Fig. 1 is a plan view of cover and cover op- 30 crating mechanism for a pit or other type of furnace;

Fig. 2 a front elevational view thereof;

Fig. 3 a sectional elevation taken along the line 3--3, Fig. 1; 35 Fig. 4 a sectional elevation taken along the line 44, Fig. 1;

Fig. 5 a cross-sectional view of a fragmentary portion of the cover and roof illustrating a granular yielding seal; and

40 Fig. 6 a similar view of a cover edge seal in accordance with Fig. 3 of the drawing.

The structure of Figs. 1 to 6 inclusive illustrates a cover for closing and sealing a furnace and the operating mechanism for the cover mem- 45 her. The cover consists of a refractory material I, Fig. 4, mounted on channels 2 which are suspended by I-beams 3 from a plurality of wheeled axles 4, the wheels 5 of which operate on rails or tracks 6. The cover I is attached to brackets'3a in which shafts 4a are journalled. The cover is adapted to be raised and lowered by levers la and lb and the carriage is moved laterally to uncover the furnace chamber and expose the hearth to charge or remove ingotsor the like. The 55 cover is raised on the carriage by means of cranks 1, Fig. 1, driven by shaft 9 which actuates links 8 that are connected to levers la, which are mounted and keyed on the shafts 4a. The levers lb are mounted on shaft 4a and on the wheeled axles 4, which latter act as fulcrums on which the cover is raised and lowered. Shaft 9 is driven through a transmission N), Fig. 1, by a motor-llv which is provided with a magnetic brake Ila. The wheeled axles 4 are driven by sprocket chains 12, Fig. 1, engaging sprocket wheels l3 of drive 10 mechanism l4, driven by a motor l5 to move the cover to open and close the furnace chamber. The cover I spans the opening of the furnace, such as a soaking pit furnace and extends over the groove or channel I6 of the side walls ll of the furnace. The grooves 16 are filled with calcined flint, clay, sand or other granular refractory material l8, and a refractory slab l9 having a V-wedge 20 is adapted to project into the sand IS, the inclination of the wedge 20 20 being greater than the angle of repose of the sealing material l8 so that when the cover is lowered, the sealing material will always provide a seal around the wedge 20. In lowering the cover. a crank la keyed on shaft 4a, through the retarding effect of fluidv piston mechanism 2|, will gradually cause the refractory sealing member 20 to force itself into the granular seal l8. Valves 22 are provided to control the bypassing of the fluid from either side of the piston, the adjustment being such that the cover may be rapidly lifted and its lowering movement retarded as desired.

In the construction shown in Fig. 4, metal plates 23 are employed in addition to the refractory slabs l9 to extend beyond the wedge 20 of the refractory slabs. The refractory members l9 and metal plates 23 are held on cover I by clamping shoes 24, Fig. 5. The'cross-sectional view of Fig. 6 illustrates the use of refrac- 0 tory wedge-shaped side members IS on all sides of the cover member, also clearly showing the clamping shoes 24 held by bolts 25 adjacent the face of channel 26 to the channel members 21 of the cover. Fig. 5 illustrates the combined refractory slabs and steel plates which are used on the side of the cover. that is, the side longitudinal to the direction of movement of the cover when motor I5 is operated.

Thus the cover is adapted to be raised a sufficient amount to lift the refractory wedges l9 out of the seal and yet retain the ends of the metal plates 23 in the seal on one side, which seal is maintained during the lateral movement of the cover. The cover is moved a distance in either direction on its supporting tracks to produce a desired opening for the removal or charging of ingots, and after the ingot is, removed or charged the cover is returned to its central position. The eflicient sealing of the furnace is important for saving of fuel and eliminates destruction of the edges of the cover by flames belching from the furnace when it should be normally tight. The cushioning of the descending cover by the liquid displacement cylinders prevents unnecessary shock to the cover refractories during the descending movement, the movements of the cover being utilized to exercise control on the gas and air supply passages of the furnace as is disclosed in the above mentioned co,- pending application serially numbered 733,812, filed July 5, 1934, of which the present case is a subdivision.

Although one embodiment of the invention has been herein illustrated and described, it will be apparent to those skilled in the art that various modifications may be made in the details of construction without departing from the principles herein set forth? We claim:

1. In an industrial heating furnace,. a combustion chamber having an opening at the top thereof, a cover for said opening, a granular refractory seal for said cover around said opening, means on said cover extending into said seal when the cover is in place over the furnace opening, means for raising the cover to partially break the seal, and means for traversing the cover while in its raised position while maintaining a partial seal with the furnace.

2. In an industrial heating furnace, a combustion chamber having an opening at the top thereof, a cover for said opening, a granular refractory seal for said cover around said opening, means on said cover extending into said seal when the cover is in place over the furnace opening, means for partially breaking the seal while maintaining the cover in register with the furnace opening, and means for traversing the cover -while maintaining a partial seal with the furnace wall.

3. In an ingot heating furnace open at the top and having a sand seal in the side walls extendlng around said opening, a pair of rails adjacent the furnace opening,' a cover suspended from wheeled axles on said rails, said cover being out of contact with the walls of the furnace and having sealing members for engagement with the sand seal around the furnace opening, means for partially breaking the seal while maintaining the cover in register with the furnace opening, and means for traversing the cover on its supporting rails in either direction of the furnace opening to expose only the portionof the furnace into which or from which the ingots are to be charged or removed.

4. In an industrial heating furnace, a combusticn chamber having an opening at the top.

thereof, a cover for said opening, a pair of rails at opposite sides of the opening, a granular refractory seal for the cover around the opening,

sealing means extending from the cover into the refractory seal when the cover is in place over 

